Field of the Invention
This invention relates to a method and a system for transmitting compressed audio data without expansion and for recording the data on the receiving side as compressed signals in which the status of a recording medium is detected for announcing an error and displaying an error message.
There has so far been known a magneto-optical disc, termed a mini-disc (trademark), which is a recordable and reproducible disc-shaped recording medium of approximately 64 mm in diameter housed within a cartridge. This magneto-optical disc can record stereo audio signals continuing for about 74 minutes in accordance with the Adaptive Transform Acoustic Coding (ATRAC) system. This magneto-optical disc can duplicate audio data because it can record the information in distinction from the conventional digital audio disc known as a compact disc (trademark).
Similarly to the conventional digital audio disc, the magneto-optical disc permits random accessing to the audio data recorded thereon, because an area for Table-Of-Contents information (TOC information) for supervising the recorded audio data is provided in this magneto-optical disc in addition to an area for recording audio data. Therefore, if audio data is overwritten on the magneto-optical disc carrying recorded audio data, it is possible to erase or edit musical titles by rewriting the TOC information without erasing actual audio data.
There may be envisaged an audio dubbing system in which, for recording audio data compressed to approximately 1/5 on a magneto-optical disc, compressed audio data are directly stored in a server and read out therefrom so as to be recorded on a server side hard disc, and in which the compressed audio data are transmitted without expansion for recording on the receiving side.
It may be feared that if, in such audio dubbing system, the recording capacity of a magneto-optical disc is short, the recording area is destroyed partially or entirely, a replay-only disc is inserted or a mistaken recording inhibiting pawl provided in a cartridge of the magneto-optical disc is locked, the recording operation is not performed as regularly. This defective state can, however, be repaired if, when the user dubs the data from the compact disc to the magneto-optical disc, the status of the loaded magneto-optical disc is detected in the recording device to issue an alarm, since the user can then halt and re-initiate the dubbing operation even if the transmission of audio data from the compact disc is already started.
On the other hand, in an audio dubbing system in which the audio data transmitted from the server present in a remote place over a transmission route, if the user once requests a desired musical title, the server transmits the audio data without regard to the status of the recording medium owned by the client.
If the user inadvertently loads the replay-only disc on the recording device, the audio data transmitted cannot be recorded on the replay-only disc, such that the audio data transmitted cannot be dubbed on the client side.
Since the server charges the fee for the transmitted audio data, there is incurred monetary loss to the user.
Moreover, since the transmitted audio data is in the form of non-decoded compressed data, the user cannot tentatively hear the audio data, such that the transmitted audio data is of no avail to the user.